


Pinky Promise?

by TheSleeplessWriter



Category: Sherlock (TV)
Genre: Age Regression/De-Aging, Ageplay, Crayons, Experiments, F/M, Fanfiction, Fluff, M/M, Molly-centric, Multi, Nonsexual, Spanking, Temper Tantrums, Timeouts
Language: English
Status: Completed
Published: 2017-03-15
Updated: 2017-03-15
Packaged: 2018-10-05 15:11:11
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,394
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10311011
Author URL: https://archiveofourown.org/users/TheSleeplessWriter/pseuds/TheSleeplessWriter
Summary: It all started with a competition to mix up the most corrosive liquid in five minutes. I wonder who's idea that was?





	

**Author's Note:**

  * For [sadistically_sweet](https://archiveofourown.org/users/sadistically_sweet/gifts).



> Hi! This is my very first ageplay fic, and I'm a little more than nervous. I've been curious on this genre and wanted to experiment a little. This is dedicated to sadistically_sweet ,as I love their works and has seriously inspired me to take a leap of faith and write this story.

"Maully!" Sherlock shouts happily, jumping off the couch to greet her. He had been waiting all day for her to get off work. 

"Hi Lock." Molly says quietly with a smile as she looks around the flat. "Where's Daddy?" 

"He's in the shower." Sherlock replies with a devious smirk and eyebrow wiggle. He looks every bit the naughty child, dressed in a dark purple tee and black shorts. He refuses to wear anything that is not black, purple, or blue. Go ahead and try to dress him in pastels, he'll kick up a grand fuss. 

Molly, however, loves light colors. Pale blue is her favorite, just like the capris she is wearing. A soft yellow blouse completes her look. A pink dummy is held in her nervous hands. She's still a little new to this and they are going slow, never aging very small. 

"C'mon." Sherlock beckons, walking towards the kitchen, an excited look on his face. He starts to pull out his vials, beakers, and suspicious smelling liquids, dropping them down with a loud clank. 

"Are we s'posed to touch this?" Molly asks despite the grin growing on her face. She sits across from Sherlock at the table, poking at the glass bottles. Any chance to mess with science is fun. 

"It's okay." Sherlock says confidently, pushing half of the equipment to Molly's side of the table. Daddy would be so proud, he's sharing and everything. 

"Five minutes to make the most corrosive liquid." He challenges, popping a skull dummy into his mouth. 

Molly pauses, her eyes running over all the bright colors and possibilities. "You're on, Lock." She finally says, a devilish smile on her face. 

The timer is set, and the game is on. Sherlock leave a mess behind as he races to add as many dangerous compounds into his vial as possible. Two minutes in, Molly is a little stressed and picks up her dummy. It's still difficult to ease into a completely different mindset. Before she can think too much on transitioning, she remembers the competition, dumping in a spoonful of acid. 

For the remainder of the time, nothing could be heard but the slight sucking of dummies and concentrated breathing. Just before the time is up, a certain Daddy walks in. 

"What are you two doing?" John asks, biting his tongue to stop from laughing at the way those two jump. 

What's not so funny is that in her surprise, Molly spilled nitric acid onto her fingers. The pain shoves her into her little headspace, a cry escaping her lips. The timer goes off, coinciding with Molly's second -and louder- cry. John rushes to action, grabbing her shoulder to lead her to the sink.

"Daddy!" She tearfully says as he carefully rinses her hand. 

"It's okay. It's okay." John reassures, embracing her and pressing a kiss to the top of her head. John turns his head to the ringleader of these two, who most certainly orchestrated this idea. The little detective knew full well that experiments were off-limits when he was small. 

"William Sherlock Scott Holmes. Corner, now!" John does his best not to shout. He doesn't really succeed, but hey, he tried. 

Once the burn is bandaged and taken care of, Molly is sent off to the opposite corner of Sherlock's. She frowns in annoyance, her head starting to hurt along with her hand. She angrily scrubs stray tears away with back of her knuckles. Rules swim around in her head, and she never remembered hearing one on experiments. It was unfair and confusing, subsequently making her feel older and crosser. 

John checks on Sherlock, who is sitting near the corner. "Sherlock, if you don't immediately put your bum in that corner, I will smack it." It definitely wasn't a bluff. 

Sherlock doesn't move, instead muttering some unintelligible yet rude sounding complaints. 

John walks over, lifting Sherlock by the arm to land one sharp smack on his bum before firmly placing his nose in the corner. 

"Ah, Daddy!" Sherlock whines. 

"That was your last warning." John says before seating himself on his chair and opening a newspaper. 

Sherlock crosses his arms and humphs, but decides to stay silent. Finally making use of that clever brain. 

After ten minutes, John calls the two culprits over. 

"That was very dangerous, the game you two played. You are much too small for that." John starts. 

"I know what I'm doing." Sherlock interjects, an impudent pout on his lips visible despite the dummy. 

"Oh really. You forgot to wear gloves, goggles, and aprons. You certainly know what you're doing." John can't help the sarcasm this time. Seeing the frown on their faces, he softens. "You know the rules. They're for your own good. I don't stay up all night thinking up new rules to make you miserable."

Even though she's the quietest, Molly can't shake off how upset she is. It was just a timeout, yet it felt like more. 

"How bout we go color for a bit?" John suggests, leaving his chair and kneeling to grab a box under the coffee table. 

The three lie on their stomachs on the floor, coloring some science-themed coloring books. Anything for the little geeks. 

As she is coloring an illustration of the vital organs, - honestly, kids do this for homework - Molly reaches for the burgundy crayon she needs for the liver. 

Only Sherlock has it, the crayon clenched tight in his hand as he scribbles hard. 

"Give me that crayon." Molly demands, her hand outstretched. 

"Is that how you ask, Molly?" John reprimands, coloring in a giraffe -because that's what normal coloring books have-. 

"PLEASE." She adds harshly. 

"Nuh-uh, I'm using it for the lava." Sherlock says, pointing to the surprisingly well illustrated and realistic volcano. 

"Just give it to me!" Molly repeats, her voice rising. 

"No!" Sherlock's voice matches her tone as he grows irritated. "I'm using it."

"Just wait your turn." John advises calmly. 

"I need it!" Molly insists, her eyes filling with tears, which she furiously wipes away. Why weren't they listening?

"Molly, please calm do-" 

"NO!" She screams, her breathing is fast and ragged, her voice choking on tears. 

Her hands move quickly, and Molly wrenches the crayon from Sherlock's hand. 

"Molly Hooper, give him the crayon back." All sternness returns to John's voice, and he stares her down with the Look. 

Molly looks from her coloring book and back to John. Her head ever so hurts and all she feels is her throat drying. 

"One." John counts, his firm stare never wavering. Molly's eyes fill with new tears, as she holds the crayon tight in her hand. "Two." Why is this all so complicated?

Just as John reaches three, Molly breaks the crayon in her hand before tossing it to Sherlock. She stands and runs off to the bathroom. 

"Molly!" John shouts in exasperation, standing to chase after her. Normally, he would assume she was pulling a Sherlock and misbehaving for attention and punishment. But it all seems a little too raw and accidental. She doesn't want punishment, for she would have shown it differently. 

In her haste, Molly forgot to lock the door. She sits on the edge of the bathtub, forcing herself to stop crying. It results in pitiful choking sounds.

"What's wrong, Love?" John asked, sitting next to her and placing an arm around her thin form. 

"I didn't know we weren't s'posed to experiment. Lock said it was okay." Molly manages through her sniffles as she snuggles against John's tan jumper. 

"Well, Sherlock will definitely apologize for lying. Don't you think that experimenting would fall under the "Don't endanger yourself rule"?" John says, patting her shoulder. She nods shyly. 

"Is that it, Love?" John prods, feeling that there is more. 

"I-I don't wanna complain or argue. I love this, and I don't want to mess it all up." She holds tight to John. "Sherlock was yours first. It's easier to leave me. And then I'd be like before. Alone." Her grip tightens at the thought of John leaving. 

"We'd never leave you, Molls. We wouldn't be doing this if we didn't love you. Don't be afraid to ask or even to complain. It's all okay." He reassures, kissing her forehead.

"Pinky promise?" Molly asks, her voice hoarse from crying. 

John smiles, linking his pinky with hers. "Of course. We'd be lost without our Molly."

**Author's Note:**

> Thanks for reading, and feel free to leave kudos, comments, and constructive criticism:)


End file.
